Ratchet wrench



L. E. BACON RATGHET WRENCH Feb. 8, 1966 Filed Oct. 25, 1965 INVENTORLouis E. Bacon ATTORNEY United States Patent 3,233,481 RATCHET WRENCHLouis E. Bacon, Canton, Ohio, assignor, by mesne assignments, toKelsey-Hayes Company, a corporation of Delaware Filed Oct. 25, 1963,Ser. No. 318,988 6 Claims. (Cl. 8163) This invention relates toratchets, and more particularly to ratchet wrenches having a reversingshifter mechanism. In one well known type of ratchet wrench a handle isoperatively connected by means of a ratchet and pawl -mechanism with arotatable head, and the direction of rotation of the head may bereversed by means of a shifter mechanism to cause the head to be rotatedalternately in opposite directions. Such .ratchets may be subdividedinto those of the center shifter type, wherein the shifter is locatedcentrally of the head, and remote shifters wherein the shifter may belocated remotely thereof on the handle. Ratchets of the center shiftertype are generally more economical toproduce, dueto their requirement offewer parts and less machining than 'usually the case in the remoteshifter type. However, a disadvantage frequently encountered heretoforein the center-shifter type is difliculty in actuating the shiftermechanism with only one hand. Thus, due to the lack of sufilcientleverage in the shift mechanism of the center shifter type ratchets, asa practical matter it has been necessary to employ two hands toaccomplish shifting, one hand to hold the handle steady and the otherhand to operate the shift lever.

- One of the most important disadvantages encountered in the ratchetwrenches produced commercially heretofore, has been the difliculty ofdisassembly and reassembly of the ratchets in the field, whenever itbecomes necessary to replace any worn parts. The particular interlockingof the internal mechanism in the prior art ratchet wrenches has madesuch disassembly and reassembly a very tricky operation requiringconsiderable kill and experience for accomplishment. Furthermore, in theprior art constructions the relationship of the internal moving partshas been such that jamming could readily occur.

An object of the present invention is to provide a new and improvedratchet wrench having a simplified interlocking of its internal parts topermit easy disassembly and reassembly thereof.

Another object of the invention is to provide a new and improvedreversing shifter mechanism for a reversible ratchet wrench, havingleverage sufiicient to facilitate the shifting operation.

Still-another object of the invention is to provide a new and improvedratchet wrench of rugged and sturdy construction which is efficient andreliable in operation.

Other objects and advantages of the invention will become evident in thefollowing detailed description of a specific embodiment thereof, whenconsidered in conjunction with the appended claims, wherein:

FIG. 1 is a top plan view of a ratchet wrench embodying the invention,with the handle portion thereof omitted;

FIG. 2 is a vertical sectional view taken on the line 2-2 of FIG. 1,showing the interlocked internal mechanism, and the shifter body and thepawl pin being shown in elevation;

FIG. 3 is a horizontal sectional view taken along the line 33 of FIG. 2,showing the ratchetand pawl mechanism in one of its alternate operatingpositions;

FIG. 4 is a view corresponding to that of FIG. 3, but showing theratchet and pawl in their reversed operating position;

FIG. 5 is a side elevation view of the shifter, showing the interlockslot formed in the shifter body;

FIG. 6 is an end elevation view of said shifter, and

3,233,48l Patented Feb. 8, 1966 FIG. 7 is a fragmentary sectional viewcorresponding to that of FIGS. 3 and 4, showing the shifter body turnedto a position of non-interlocking with the pawl to permit disassembly.

In the illustrated ratchet wrench, a generally cylindrical hollow headportion 10 may be secured to an elongated handle portion (not shown) ina one-piece integral construction, or the handle may be connectedpivotally to the head by means of a hinge, for which purpose acounten-bored socket 12 is provided in a projecting lug 14 formed on oneside of the head portion 10 of the illustrated wrench. Rotatably mountedwithin the hollow head portion 10 is a generally cylindrical core 16,and a work piece engaging projection 18 of the type employed inconventional socket wrenches is secured integrally to the body of thecore 16 and projects from one side of the head 10, as shown in FIG. 2.

The cylindrical cavity defined by the hollow interior of the headportion 10 of the ratchet wrench is provided with a circumferential rowof ratchet teeth 20, which cooperate with a plurality of teeth 22 formedon opposite ends of a pivotally mounted double-ended pawl 24, best shownin FIGS. 3 and 4. The pawl 24 is removably pivotally mounted on acylindrical pawl pin 26 fitted snugly within a recess formed in the core16 parallel to but offset from the axis thereof. A shifter having agenerally cylindrical body 28 is rotatably fitted snugly within anotherrecess in the core 16, spaced from and parallel to the recess for thepawl pin 26, and off center with respect to the axial center of the core16. The shifter body 28 is provided at one. end thereof with an integralcover plate 30 above which projects an integral tapered shift lever 32designed for finger actuation by a mere flick of an operators finger orthumb. The cover plate 30 covers the two above-mentioned recesses formedin the core 16, and it retains the pawl pin 26 in place, so that thepawl 24 and its pin 26 cannot be removed from the core 16 until theshifter body 28 is first detached therefrom.

The pawl 24 is provided with an arcuate surface 34 midway between itsopposite ends, and cooperating with this surface 34 is a spring pressedplunger 36 having a rounded nose 38 to facilitate its sliding movementacross the surface 34. The plunger 36 is mounted slid'ably within atransverse socket 40 disposed at right angles with respect to the axisof the shifter body 28, as is best shown in FIGS. 5 and 6, and theplunger 36 is urged outwardly by a spring 42 to maintain the roundednose 33 in contact with the arcuate surface 34. It is evident thatrotary movement of the shifter body 28, by finger actuation of the lever32 through a small angle, causes the plunger 36 to travel acrossthearcuate surface 34 between opposite ends thereof, and that in doingso the plunger 36 moves with snap action past the dead center of thesurface 34.

When the pawl 24 and the plunger 36 are in the operating position inwhich they are shown in FIG. 3, the core 16 and its work piece engagingprojection 18 are permitted to rotate in one direction, the teeth 22being held in resilient ratchetting engagement with the circumferentialrow of teeth 20. Angular movement of the finger actuated shift lever 32causes the plunger 36 to slide across the surface 34 past dead centerand snap into the reverse operating position shown in FIG. 4, .to allowthe core 16 to rotate in the opposite direction.

The movement of the shifter body 28, and consequently of the plunger 36also, is limited by means of stop surfaces 44 formed on opposite sidesof one end of the cover plate 30, which stop surfaces 44 abut against aportion of a circular retaining rim 46 formed at one end of thecylindrical cavity defined by the hollow interior of the head 10. Thecore 16 is shown with one end thereof abutting against the rim 46 inFIG. 2, and the other end of the core 16 is held within the head bymeans of a removeable snap ring 48. Thus, the entire internal mechanismmay be removed for disassembiy, simply by detachment of the snap ring48. Then the shifter body 28 may be withdrawn from the core to byturning said body until a cutaway portion forming a vertical flatsurface 50 thereon is brought nearly or approximately into alignmentwith a corresponding fiat surface 52 formed on the interior of andextending across the core 16, as is shown in FIG. 7. During thismovement the rounded nose 3% of the plunger 36 is turned away from thepawl 24, counterclockwise as viewed in FIGS. 3 and 4, and the plunger 36is retracted completely into the socketdt} by engagement of its nose 3%with a portion of the recess in which the shifter body 28 is mounted.

During normal operation, in the two alternate operating positionsillustrated in FIGS. 3 and 4, a portion of the pawl 24 just beyond thearcuate surface-34 thereon is placed into interlocking engagement withthe wall surfaces of a transverse interlock slot 54 formedinthe shifterbody 28. The pawl 24 is constantly urged toward, one or the other of itsalternate operating positions due to the pressing action of the springpressed plunger 36, thereby maintaining interlocking and ratchettingduring normal operation. However, when the shifter body 28 is turned tocause complete retraction of the plunger 36, the resultant detachment ofthe plunger 36 from the arcuate surface 34 allows the pawl 24 to remainin its dead cent r position, or in its last ratchetting position, asshown in FIG. 7. Furthermore, in this disassembly position theabove-described interlocking is terminated by the turning of the cutawayfiat surface 50 to a point adjacent to the arcuate surface 34, therebyproviding clearance therebetween and facing the slot 54 away from thepawl 24,'so that the shifter body 28 may thereupon be withdrawn from thecore 16. Completion of the disassembly operation at this stage merelyrequires the sliding out of the pawl 24 and the pawl pin 26 from thecore 16, which is made possible by the prior removal of the cover plate30, and at that time the plunger 36 and its spring 42 then beingunrestrained can pop out of the socket 40. Reassernbly of ratchetdevices embodying the present invention may be accomplished byperforming in reverse order the abovedescribed steps of disassemb'ly.

The disassembly of the ratchet devices known heretofore has usuallyrequired the insertion of a screwdriver, or some other small-bladedinstrument, between the pawl and the plunger to force retraction of theplunger into its socket, and this has been an intricate operation due tothe small size of the ratchet devices with which the present inventionis concerned. In accordance with the present invention such retractionof the plunger is achieved merely by turning the shifter body until thenose of the plunger is engaged by the wall of the recess in which theshifter is mounted, which is quite an easy operation.

Due to the novel interlocking between the pawl 24 and the wall surfacesof the interlock slot 54 in the shifter body 28, ratchet devicesembodying the present invention are rendered sturdy and reliable inoperation, with little likelihood of the plunger or pawl becomingjammed. Furthermore, due to the offset of the turning axis of theshifter body 28 with respect to that of the core 16, the shifter lever32 is provided with sufficient leverage to facilitate the shiftingoperation, requiring only a flick of an operators finger or thumb. Itshould be observed that the taper of the shift lever 32, which slopesdownwardly in a direction away from the wrench handle and is highest ata point adjacent to the lug 14 connecting with the handle, serves toguide the operators thumb or finger to the highest point on the lever32, thereby insuring that the maximum leverage is obtained. It shouldalso be noted that the arcuate surface 34 functions during normaloperation of the ratchet device as a carnming surface 'en- ,gaged by theplunger 3 6 as a cam, to control the pivotal movement of the pawl 24 andto effect reversal of the ratchet device.

It will be obvious to those skilled in the art that various changes maybe made without departing from the spirit and the scope of theinvention, as defined by the appended claims.

I claim:

1. In a ratchet device, a generally cylindrical head having acylindrical internalcavity extending therethrough and provided with acircumferential row of ratchet teeth in said cavity, a cylindrical coremounted rotatably in said cavity and having joined thereto a work pieceengaging projection extending outwardly from the head, a doubleendedpawl mounted pivotally in said core and having pawl teeth at oppositeends thereof cooperating with the ratchet teeth in two alternateoperating positions into which said pawl may be pivotally moved,ratchetting engagement of the ratchet teeth with the pawl teeth at oneend of the pawl permitting rotation of the core in one direction andpivoting of the pawl into its alternate operating position to engage theteeth at the opposite end of the pawl permitting rotation in the reversedirection, a shifter including a generally cylindrical shifter bodymounted rotatably in the core and joined to a shift lever projectingoutwardly from the head, a spring pressed plunger mounted slidably inthe shifter body and normally urged into engagement with the pawl, saidplunger normally urging one end or the other of the pawl into engagementwith the ratchet teeth and being effective when the shift lever isactuated to cause pivoting of the pawl for reversal of the direction ofrotation of the core, said shifter body having a slot which is normallyin interlocking engagement with the pawl when the pawl is pivoted to itstwo alternate operating positions but is freed from interlocking whenthe shifter body is turned to a disasse-mhly position wherein the slotfaces away from the pawl, and means for normally preventing turning ofthe shifter body to its disassembly position until the shifter body isremoved from the head.

2. In a ratchet device, a generally cylindrical head having acylindrical internal cavity extending therethrough and provided with acircumferential row of ratchet teeth in said cavity, a cylindrical coremounted rotatably in said cavity and having joined thereto a work pieceengaging projection extending outwardly from the head, a double-endedpawl mounted pivotally in said core and having pawl teeth at oppositeends thereof cooperating with the ratchet teeth in two alternateoperating positions into which said pawl may be pivotally moved,ratchetting engagement of the ratchet teeth with the pawl teeth at oneend of the pawl permitting rotation of the core in one direction andpivoting of the pawl into its alternate operating positionto engage theteeth at the opposite end of the pawl permitting rotation in the reversedirection, a shifter including a generally cylindrical shifter bodymounted rotatably in the core and joined to a shift lever projectingoutwardly from the head, a spring pressed plunger mounted slidably in atransverse socket in the shifter body, said plunger being normallypressed into engagement with the pawl and urging one end or the other ofthe pawl into engagement with the ratchet teeth, said pawl being shiftedfor reversal of the direction of rotation of the core by angularmovement of the shift lever to cause a corresponding angular movement ofthe plunger pressed against the pawl, said shifter body having aninterlock slot which is normally in interlocking engagement with thepawl when the pawl is in its two alternate operating positions but isfreed from interlocking when the shifter is further turned to adisassembly position wherein the slot faces away from the pawl, saidplunger being completely retracted by said further turning of theshifter thereby disengaging the pawl for disassembly, and

stop means for preventing such further turning of the shifter until saidbody is first disassembled from the head. 3. The ratchet device definedby claim 2, wherein the double-ended pivoted pawl is provided midwaybetween its ends with an arcuate cam surface against which the springpressed plunger is normally urged into sliding contact, said plungersliding across said arcuate cam surface from one end to the other duringpivotal movement of the pawl between its alternate operating positions,interlocking between the pawl and the shifter body occurring beyond theends of the arcuate surface, and said surface providing clearance fordisassembly of the shifter from the pawl when the pawl is allowed topivot to its dead center position.

4. The ratchet device defined by claim 2, wherein the core is providedwith a recess in which the shifter body is rotatably mounted, turning ofthe shifter body into its disassembly position brings the plunger intoengagement with a portion of said recess to cause the plunger to becomecompletely retracted into its socket in the shifter body, and said coreand said body being provided with flat surfaces which become alignedwhen the shifter body is in its disassembly position, thereby providingclearance for disassembly.

5. In a ratchet device, a generally cylindrical head having acylindrical internal cavity extending therethrough and provided with acircumferential row of ratchet teeth in said cavity, a cylindrical coremounted rotatably in said cavity and having joined thereto a work pieceengaging projection extending outwardly from the head, a pawl pinmounted removably in a first recess in said core offset from the centerthereof, a double-ended pawl mounted pivotally on said pin and havingpawl teeth at opposite ends thereof cooperating with the ratchet teethin two alternate operating positions into which said pawl may bepivotally moved, ratcheting engagement of the ratchet teeth with thepawl teeth at one end of the pawl permitting rotation of the core in onedirection and pivoting of the pawl into its alternate operating positionto engage the teeth at the opposite end of the pawl permitting rotationin the reverse direction, ashifter including a generally cylindricalshifter body mounted rotatably in a second recess in the core spacedfrom the first recess and also offset from the center of the core, atapered shift lever projecting outwardly from the head, the taper of theshift lever and the offset of the recess in which the shifter is mountedserving to provide lever-age to facilitate angular movement of the shiftlever, a spring pressed plunger mounted slidably in a transverse socketin the shifter body, said plunger being normally pressed into engagementwith the pawl and urging one end or the other of the pawl intoengagement with the ratchet teeth, said pawl being shifted for reversalof the direction of rotation of the core by angular movement of theshift lever to cause a corresponding angular movement of the plungerpressed against the pawl, said shifter body having an interlock slotwhich is placed in interlocking engagement with the pawl when the pawlis pivoted to its two alternate operating positions but is freed frominterlocking when the shifter is turned further to a disassemblyposition wherein the slot faces away from the pawl, said plunger beingcompletely retracted by said further turning of the shifter body to itsdisassembly position by engagement with a portion of the second recessthereby disengaging the pawl for disassembly, and stop means forpreventing such further turning of the shifter body until said body isfirst disassembled from the head.

6. The ratchet device defined by claim 5, wherein the shifter body isprovided with a cover plate above which projects the tapered shiftlever, said cover plate covering said first and second recesses andthereby normally retaining the pawl and its pawl pin within the core,and opposite side edges of the cover plate serve as stop surfacesabutting alternately on opposite sides of the rim of the internal cavityin the head, thereby providing the stop means for preventing turning ofthe shifter body beyond the limits of the normal operating positions tothe disassembly position until said shifter body is first removed fromthe head.

References Cited by the Examiner UNITED STATES PATENTS 655,908 8/1900Morse 8163 1,078,059 11/1913 Mossberg 74157 X WILLIAM FELDMAN, PrimaryExaminer.

1. AIN A RATCHET DEVICE, A GENERALLY CYLINDRICAL HEAD HAVING ACYLINDRICAL INTERNAL CAVITY EXTENDING THERETHROUGH AND PROVIDED WITH ACIRCUMFERENTIAL ROW OF RATCHET TEETH IN SAID CAVITY, A CYLINDRICAL COREMOUNTED ROTATABLY IN SAID CAVITY AND HAVING JOINED THERETO A WORK PIECEENGAGING PROJECTION EXTENDING OUTWARDLY FROM THE HEAD, A DOUBLEENDEDPAWL MOUNTED PIVOTALLY IN SAID CORE AND HAVING PAWL TEETH AT OPPOSITEENDS THEROF COOPERATING WITH THE RATCHET TEETH IN TWO ALTERNATEOPERATING POSITIONS INTO WHICH SAID PAWL MAU BE PIVOTALLY MOVED,RATCHETTING ENGAGEMENT OF THE RATCHET TEETH WITH THE PAWL TEETH AT ONEEND OF THE PAWL PERMITTING ROTATION OF THE CORE IN ONE DIRECTION ANDPIVOTING OF THE PAWL INTO ITS ALTERNATE OPERATING POSITION TO ENGAGE THETEETH AT THE OPPOSITE END OF THE PAWL PERMITTING ROTATION IN THE REVERSEDIRECTION, A SHIFTER INCLUDING A GENERALLY CYLINDRICAL SHIFTER BODYMOUNTED ROTATABLY IN THE CORE AND JOINED TO A SHIFT LEVER PROJECTINGOUTWARDLY FROM THE HEAD, A SPRING PRESSED PLUNGER MOUNTED SLIDABLY INTHE SHIFTER BODY AND NORMALLY URGED INTO ENGAGEMENT WITH THE PAWL, SAIDPLUNGER NORMALLY URGING ONE END OF THE OTHER OF THE PAWL INTO ENGAGEMENTWITH THE RATCHET TEETH AND BEING EFFECTIVE WHEN THE SHIFT LEVER ISACTUATED TO CAUSE PIVOTING OF THE PAWL FOR REVERSAL OF THE DIRECTION OFROTATION OF THE CORE, SAID SHIFTER BODY HAVING A SLOT WHICH IS NORMALLYIN INTERLOCKING ENGAGEMENT WITH THE PAWL WHEN THE PAWL IS PIVOTED TO ITSTWO ALTERNATE OPERATING POSITIONS BUT IS FREED FROM INTERLOCKING WHENTHE SHIFTER BODY IS TURNED TO A DISSASSEMBLY POSITION WHEREIN THE SLOTFACES AWAY FROM THE PAWL, AND MEANS FOR NORMALLY PREVENTING TURNING OFTHE SHIFTER BODY TO ITS DISASSEMBLY POSITION UNTIL THE SHIFTER BODY ISREMOVED FROM THE HEAD.